Laboratory evaluation of a prototype photochemical chamber designed to investigate the health effects of fresh and aged vehicular exhaust emissions.
Inhal Toxicol
; 23(8): 495-505, 2011 Jul.
Article
em En
| MEDLINE
| ID: mdl-21689011
Laboratory experiments simulating atmospheric aging of motor vehicle exhaust emissions were conducted using a single vehicle and a photochemical chamber. A compact automobile was used as a source of emissions. The vehicle exhaust was diluted with ambient air to achieve carbon monoxide (CO) concentrations similar to those observed in an urban highway tunnel. With the car engine idling, it is expected that the CO concentration is a reasonable surrogate for volatile organic compounds (VOCs) emissions. Varying the amount of dilution of the exhaust gas to produce different CO concentrations, allowed adjustment of the concentrations of VOCs in the chamber to optimize production of secondary organic aerosol (SOA) needed for animal toxicological exposures. Photochemical reactions in the chamber resulted in nitric oxide (NO) depletion, nitrogen dioxide (NO2) formation, ozone (O3) accumulation, and SOA formation. A stable SOA concentration of approximately 40 µg m⻳ at a chamber mean residence time of 30 min was achieved. This relatively short mean residence time provided adequate chamber flow output for both particle characterization and animal exposures. The chamber was operated as a continuous flow reactor for animal toxicological tests. SOA mass generated from the car exhaust diluted with ambient air was almost entirely in the ultrafine mode. Chamber performance was improved by using different types of seed aerosol to provide a surface for condensation of semivolatile reaction products, thus increasing the yield of SOA. Toxicological studies using Sprague-Dawley rats found significant increases of in vivo chemiluminescence in lungs following exposure to SOA.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fotoquímica
/
Câmaras de Exposição Atmosférica
/
Emissões de Veículos
/
Poluentes Atmosféricos
Tipo de estudo:
Evaluation_studies
Limite:
Animals
Idioma:
En
Revista:
Inhal Toxicol
Assunto da revista:
TOXICOLOGIA
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Estados Unidos